Low temperature greases

ABSTRACT

DI-N-ALKYLBENZENE OILS THICKENED WITH CLAYS OR METAL SOAPS. THE GREASE MAY ALSO CONTAIN THE RUST-INHIBITING COMPINATION OF LEAD NAPHTHENATE, DIDODECYL DIMETHYL QUATERNARY AMMONIUM NITRITE OR NITRATE, AND A FATTY IMIDAZOLINE ALKYL DIAMINE DICAPRYLATE.

United States Patent O US. Cl. 252--28 Claims ABSTRACT OF THE DISCLOSURE Di-n-alkylbenzene oils thickened with clays or metal soaps. The greases may also contain the rust-inhibiting combination of lead naphthenate, didodecyl dimethyl quaternary ammonium nitrite or nitrate, and a fatty imidazoline alkyl diamine dicaprylate.

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part of application Ser. No. 860,091, filed Sept. 22, 1969, and now abandoned.

BACKGROUND AND PRIOR ART A need for greases having good low temperature properties has existed for many years. The discovery of oil on the North Slope of Alaska has intensified this need due to the increasing amount of machinery and equipment which is being exposed to the arctic climate.

The present invention is concerned with grease compositions which have excellent low temperature properties. Some of the grease compositions of our invention are pumpable at temperatures as low as 60 F. Flow properties are so good that they can be dispensed with ordinary hand-type grease guns.

While low temperature grease compositions are known, it is not known to prepare satisfactory low temperature greases using a hydrocarbon lubricant. Esters and other non-hydrocarbon vehicles having excellent low temperature properties are customarily used in this art since conventional hydrocarbons lack the combination of nonvolatility and viscosity-temperature behavior that is needed.

BRIEF SUMMARY OF THE INVENTION Broadly stated, the present invention relates to a lubricating grease, having extreme low temperature pumpability properties, comprising a major proportion of a synthetic hydrocarbon lubricant and a minor grease-forming amount of a conventional grease-forming agent, said synthetic hydrocarbon lubricant containing at least 60 weight percent di-n-alkylbenzenes, said di-n-alkylbenzenes having a molecular weight in the range of from about 350 to about 460 and having alkyl groups which contain from 6 to 18 carbon atoms.

In one preferred embodiment, the present invention relates to a lubricating grease, having extreme low temperature properties, comprising a major proportion of a synthetic hydrocarbon lubricant and a minor greaseforming amount of a modified clay grease-forming agent, said synthetic hydrocarbon lubricant being as described in the immediate foregoing.

In a second preferred embodiment, the present invention relates to a lubricating grease, having extreme low temperature properties, comprising a major proportion of a synthetic hydrocarbon lubricant, as described in the foregoing, a grease-forming amount of a lithium soap grease-forming agent and a rust-inhibiting amount of a combination of lead naphthenate, didodecyl dimethyl 3,730,896 Patented May 1., 1973 uaternary ammonium nitrite (or nitrate) and a fatty imidazoline alkyl diamine dicaprylate.

DETAILED DESCRIPTION Synthetic hydrocarbon lubricant The synthetic hydrocarbon lubricant used to form the greases of my invention is characterized as containing a major proportion of dim-alkylbenzenes. The term nalkylbenzenes as used herein refers to benzenes containing 21. substantially straight chain alkyl group, wherein, preferably, at least percent of the alkyl substituents are bonded to the benzene nucleus through a secondary carbon atom of the respective alkyl group. While we prefer the term n-alkylbenzenes other terms such as linear alkylbenzenes or straight-chain alkylbenzenes, are equally descriptive.

The synthetic hydrocarbon composition contains at least 60, preferably at least 75, Weight percent di-nalkylbenzenes. The remainder of the composition is a mixture of alkyl-substituted tetrahydronaphthalenes and indanes, indenes, diphenylalkanes, naphthalenes, and alkyl-substituted naphthalenes.

One means of preparing the di-n-alkylbenzenes is by alkylating benzene with suitable alkyl groups. A preferred method of preparing the synthetic hydrocarbon composition is by the disproportionation of mono-n-alkylbenzenes using HF-BF aluminum bromide or aluminum chloride, preferably the latter, as the catalyst. Inasmuch as the product prepared by the disproportionation process is preferred in my invention, the disproportionation process will be described in detail.

Suitable mono-n-alkylbenzenes are those containing from about 6 to about 18 carbon atoms in the alkyl groups. Preferably, the alkyl groups of the mono-n-alkylbenzenes contain from about 10 to about 15 carbon atoms. The term n-alkylbenzenes has been defined in the foregoing.

In addition to pure mono-n-alkylbenzenes meeting the foregoing description the disproportionated product used in the method and compositions of my invention can be prepared using mixtures of the described pure mono-nalkylbenzenes and heterogenous hydrocarbon compositions containing substantial amounts of mixtures of the described mono-n-alkylbenzenes.

A particularly suitable material for use in preparing the disproportionated product is a composition, containing a substantial amount of mono-n-alkylbenzenes conforming to the foregoing description, produced in accordance with the process of US. Pat. No. 3,316,294. Briefly, US. 3,316,294 relates to a process of preparing a detergent alkylate, wherein the process comprises the following steps, broadly stated: (a) separating a fraction of substantially straight-chain C -C hydrocarbons from a petroleum distillate substantially free of olefins and containing said straight-chain hydrocarbons together with non-straight chain hydrocarbons, (b) chlorinating said fraction to the extent whereby between about and about 35 mole percent of the straight-chain hydrocarbons present are substantially only mono-chlorinated, (c) alkylating an aromatic compound, e.g. benzene, with the chlorination product of step (b) in the presence of an alkylation catalyst, and (d) recovering from the reaction mass, by distillation, a fraction consisting essentially of mono-nalkylbenzenes.

\While US. 3,316,294 concerns a process which can use C to C hydrocarbons the present invention uses hydrocarbons which can contain from about 6 to about 18 carbon atoms. The 0 -0 hydrocarbons can be obtained by a modification of the process described as step (a) of US. 3,316,294. In addition, other means of obtaining a C C hydrocarbon fraction will be apparent to those'skilled in this art. When it is desired to use an alkylbenzene containing to carbon atoms in the alkyl group, this selection can be made either in the initial feedstock or by fractionation of the alkylbenzene product. N-alkylbenzenes of the type described in the foregoing are available under the trademarks Nalkylene 500 and Nalkylene 600 from Continental Oil Company. These materials have the following typical properties:

Nalkylene 500 Test Typical value Test method Boiling range F.) 535-595 ASTM D-447. Bromine No 0.05 mam. ASTM D-1158. Average molecular weight. 213F241... Mass spec. Color, Saybolt Specific gravity (/20). 085 0.87 ASTM D-287. Viscosity (Saybolt seconds) 4045 at 100 F. ASTM 88-44.

N alkyleue 600 Process conditions for disproportionation reaction Preferably, the disproportionation reaction is conducted using aluminum chloride as the catalyst. The amount of the catalyst which is used can vary from about 0.1 weight percent to about 10 Weight percent based on the mono-nalkylbenzene starting material. Preferably, the amount of catalyst is from about 0.5 weight percent to about 5 Weight percent.

In some cases it is desirable to use a proton-donor promoter with the aluminum chloride catalyst. Suitable promoters include any material which, when added to the catalyst, yields a proton. Preferred promoters are hydrogen chloride and water. The amount of promoter is typically about 4 weight percent based on the weight of the catalyst employed. It should be emphasized that anyone skilled in this art can readily determine the necessity of using a promoter and the amount of promoter, if used.

The disproportionation process, suitably, is conducted at a temperature of from about 20 C. to about 130 C. Since maximum yields of the di-n-alkylbenzenes are obtained at temperatures between about 65 C. and 120 C., these temperatures are preferred. The most preferred temperature is about 100 C. When this temperature is used, preferably the amount of catalyst is from about 0.75 to about 2 weight percent.

Following the reaction, the reaction mass is distilled in order to remove the benzene, paraffins and unreacted mono-n-alkylbenzenes. The desired product is the disproportionated material distilling in the range of about 165 C. to about 300 C. at 5 mm. Hg. This material has an average molecular weight in the range of about 350 to about 460. In conducting the distillation, more suitably the lower c-ut point is 185 C. at 5 mm. Hg. Preferably, the lower cut point is 197 C. at 5 mm. Hg.

In some instances the desired fraction is obtained by distilling from the disproportionated product a select fraction or overhead amounting to from about 10 to about 90 percent of the disproportionate.

Properties of disproportionated product The disproportionated product has the following properties:

Viscosity index 80 to 116. Pour point, F. 40 to 80. Molecular weight 350 to 460.

In addition, the disproportionated product typically has the following chemical composition, as indicated by mass spectrometer analysis.

4 Component: Percent by wt.

Di-n-alkylbenzenes 64 to 85. Alkyl substituted tetrahydronaphthalenes and indanes 8 to 25. Indenes Less than 4. Diphenylalkanes Less than 5.

Grease-forming agents Any of the conventional grease-forming agents can be used to prepare the greases of our invention. As is well .known, most of the greases of commerce use metal soaps prepared by saponifying fats and oils of animal, vegetable or marine origin. In addition to the preceding, other saponifiable materials include rosin oil, naphthenic acids, sulfonic acids, synthetic fatty acids, montan wax and wool grease. The metals of the grease-forming agent can be aluminum, barium, calcium, lithium, sodium, magnesium, lead or strontium. Particularly suitable grease-forming agents for our invention include the lithium and calcium fatty acid soaps.

In addition to the preceding, various types of chemically or physically modified clays have been used as greaseforming agents. Examples of suitable clays for modification and subsequent use as a grease-forming agent include bentonite, saponite, attapulgite, zeolite and fullers earth. Surprisingly, we have found that the use of a modified clay grease-forming agent results in greases having a lower pumpability than lithium fatty acid greases. In view of this, lubricating greases prepared from modified clays are preferred in our invention.

Of the modified clays, the modified bentonites are preferred as the grease-forming agent. It is believed that the term modified bentonite is now well-understood in the grease art. The book by C. J. Boner entitled Manufacture and Application of Lubricating Greases, (Reinhold, New York1954) on pages 724 and 725, describes modified bentonites. In order to make our disclosure even more complete, this portion of the Boner bok, and the references cited therein, are made a part of this disclosure.

Amounts of materials Suitably, the amount of grease-forming agent which is used in the greases of our invention is in the range of from about 1 to about 30 weight percent. Preferably, the amount of grease-forming agent is in the range of about 5 to about 10 weight percent. As is Well-known in the grease art, varying the amount of grease-forming agent affects the consistency of the grease product.

Use of additives Various additives, such as rust inhibitors, oxidation inhibitors, lubricity agents, extreme pressure agents, stringiness agents and the like, may be added to the grease of our invention.

Rust inhibited lithium grease This embodiment of our invention concerns a rustinhibited, low-temperature grease composition comprising a major proportion of a synthetic hydrocarbon lubricant, as described in the foregoing, a grease-forming amount of a lithium soap grease-forming agent and a rust-inhibiting amount of a combination of lead naphthenate, didodecyl dimethyl quaternary ammonium nitrite (or nitrate) and a fatty imidazoline alkyl diamine dicaprylate. Since this particular rust inhibitor combination was found not to provide protection in salt water environments when used in a conventional lithium soap-petroleum oil grease, it is surprising that it provides salt water rust protection in a lithium soap-synthetic hydrocarbon lubricant grease.

Suitable lithium soaps for this embodiment of our invention include any of the lithium soaps described hereinbefore. More suitably, the lithium soap is derived from a fatty acid; preferably, it is derived from 12-hydroxy stearic acid.

The amount of grease-forming agent for this embodiment is the same as described in the foregoing.

Rust-inhibiting additive combination Lead naphthenate.-The lead naphthenate which is used in the grease of this embodiment of our invention can be any commercially available lead naphthenate. A commercial grade of lead naphthenate containing about 30 percent, by weight, lead has been particularly suitable.

Quaternary ammonium nitrite (or nitrate). The dialkyl dimethyl quaternary ammonium nitrite or nitrate which is used in the grease of this embodiment of our invention can be represented by the following formula:

Percent arquad chloride Percent arquad nitrite Apparent molecular weig Average percent nitrogen. Solvent carrier (isopropanol) Specific gravity. Flash point F Fire point, F

Fatty irnidazoline diamine dicapryIate.-This material is the reaction product of 1 or 2 moles (preferably 2 moles) of caprylic acid and a fatty imidazoline alkyl diamine. The fatty imidazoline alkyl diamine is represented by the following structural formula:

wherein R is mixed heptadecenyl (oleic) or mixed heptadienyl (linoleic).

A particularly suitable material is available from Nalco Chemical Company under the trade name Nalcamine SCC135. This material is the reaction product of one to two moles of caprylic acid and one mole of Nalcamine G397, which is a mixed heptadecenyl and heptadecadienyl imidazoline alkyl diamine.

Relative amounts of materials in rust-inhibiting additive combination The amounts of the materials which are used in grease of this embodiment of our invention are as follows (in percent by weight of total grease composition):

Suitable More suitable Preferred Lead naphthenate 1 -3 1. 5-2. 5 2. 0 Quaternary ammonium nitrite or nitrate 1-4 1. 25-2 1. 5 Fatty imidazoline alkyl diamine dicapryltte 0. 5-2 0. 75-1. 25 1. 0

In order to disclose the nature of the present invention still more clearly, the following illustrative examples will be given. It is to be understood that the invention is not to be limited to the specific conditions or details set forth in these examples except insofar as such limitations are specified in the appended claims.

Rust test method In some instances the rust test method which was used to evaluate the greases described herein was a modification of ASTM D-l743-64. Since the original method is quite mild it was modified to provide a more severe method. First, in some instances the method was modified by substituting lake water, sea water or synthetic sea water (ASTM Method D665-IP gives composition) for the distilled water called for by the original method. Sec- 7 ondly, the severity of the method was increased by the following changes in the thrust-loaded, run-in procedure:

(a) after the 10 second rotation period the bearing was immersed in salt water for 10 seconds (Section 8f, ASTM D-l743-64) (b) the hearing was then rotated a second time in accordance with paragraph 8h and again immersed in salt water.

Following (b) the bearing assembly was placed in a glass jar to which 5 ml. of salt water had been added. The jar was sealed and stored in a dark cabinet at 77 F. for a specified time.

In summary, the original ASTM method specifies that the test bearing, packed with 2 grams of grease and rotated, be dipped in distilled water just prior to storage in a sealed jar over 5 ml. of distilled water. The severity of the test has been increased by (1) immersing the packed bearing in salt water, (2) rotation under a thrust load to distribute fully the salt water, (3) a second immersion in salt water, and (4) storage in a salt water environment.

EXAMPLE 1 This example concerns the preparation of the synthetic hydrocarbon lubricant used to prepare the greases described herein. The synthetic hydrocarbon lubricant was a plant batch of disproportionated product prepared as follows:

The reaction vessel was a 3000-gallon, stirred-kettle reactor, fitted for heating, controlled addition of liquids and solids and introduction of gaseous materials. Nalkylone 600 and AlCl were fed continuously to the reaction vessel at rates of :10 and 8:4 pounds per minute, respectively. Hydrogen chloride gas was also fed into the reactor at a rate of 4:1 s.c.f. per minute. The level of reaction mass in the reactor was maintained to afford a residence time of 1.75 :0.25 hours. As the crude product was removed continuously from the reactor monitoring by partition chromatography analysis indicated that it contained 5 weight percent benzene, 15 weight percent paraffins, 55 weight percent unreacted monoalkylbenzenes and 25 weight percent dialkylbenzenes. The crude product was allowed to settle and the AlCl sludge was removed. The remaining crude product was then contacted with 2 volumes of 15:10 weight percent caustic solution. Following this, the crude product was contacted with 4:1 volumes of water to remove the residual caustic. The

neutralized crude product was then distilled recovering the following fractions:

Benzene: 70225 F. at 750 mm. Hg.

Parafiins: 225-290 F. at mm. Hg.

Monoalkylbenzene: 290330 F. at 12 mm. Hg.

Disproportionation product: Above 330 F. at 12 mm.

The disproportionation product was subjected to a further fractionation to remove 85 :10 weight percent overhead boiling between 450 and 850 F. at 760 mm. Hg. The residue was set aside. The overhead product was the desired disproportionated product (164,000 pounds were produced). The disproportionated product had the following physical properties:

Viscosity, cs.:

210 F. 5.02 Pour point, F. 75 Flash point, COC, F. 448 Fire point, COC, F 500 It had the following chemical analysis: Component: Wt. percent Dialkylbenzenes 74.3 Alkylated Tetralins 19.1 Diphenylalkanes 2.0 Indenes 2.5

Miscellaneous 2.1

*By mass spectrometry.

EXAMPLE 2 Materials used: Grams Synthetic hydrocarbon lubricant 3,200 Calcium hydroxide 108 Water 108 IZ-hydroxy stearic acid 700 *From Example 1.

The synthetic hydrocarbon lubricant and calcium hydroxide were added to a Ross mixer and stirred until thoroughly mixed. The water was added and the resulting admixture was heated to 120 F., at which time the 12- hydroxy stearic acid was added. The total admixture was heated slowly to 253F., whereupon a smooth, heavy grease was formed.

The above-described grease was reduced in consistency with additional synthetic hydrocarbon lubricant. Rust inhibitors and an antioxidant were added to the composition. The admixture was thoroughly mixed and the total mass of grease was milled in a Charlotte Colloid Mill set at 0.003" clearance. A grease was obtained having the following composition and properties:

Wt. percent Synthetic hydrocarbon lubricant 86.35 Calcium 12-hydroxy stearate 8.61 Ca(OH) 0.24 Lead naphthenate 2.0 Arquad 2C nitrite 1.5 Nalco SCC 135 1.0 Ortholeum 300 0.3

Penetration (60 strokes)--345.

*Antioxidant.

This resultant grease was then tested for rust preventive properties using salt water and the modified ASTMDF 1743 test method. After two weeks on test only trace corrosion was observed. Using the same grease and the standard ASTMD-l743 test method resulted in perfect, non-rusted bearings.

EXAMPLE 3 This example shows the preparation of a lithium 12- hydroxy stearate grease using the synthetic hydrocarbon lubricant of Example 1.

The grease was prepared by simply adding preformed lithium 12-hydroxy stearate soap (from Witco Chemical Company) and the synthetic hydrocarbon lubricant to a mixer. The contents of the mixer were heated to about 400 F. at which time they were poured into pans and allowed to cool to ambient temperatures. A grease formed, which was then milled, additives were added, and the composition was thoroughly mixed at about 250 F. The composition and properties of the grease were as follows:

Wt. percent Lithium 12-hydroxy stearate 4.77 Synthetic hydrocarbon lubricant 90.57

Lead naphthenate 2.00 Nalco" SCC 1.00 Arquad 2C nitrite 1.50 Ortholeum 300 0.30

Penetration (60 strokes)--345.

The grease of this example was tested for rust preventive properties using the modified ASTMD-l743 test method, with salt water. After two weeks testing, the bearings were rust-free. Rust-free hearings were also obtained using the standard ASTMD-1743 test, with distilled water.

EXAMPLE 4 For purposes of comparison a grease similar to that in Example 3 was prepared. The sole difference was that instead of the synthetic hydrocarbon lubricant there was used a paraifinic petroleum mineral oil having a viscosity of about 100 SSU at 100 F.

Using the grease of this example and the modified ASTMD1743 test method, the hearings were 100% rusted after only one week.

EXAMPLE 5 This example illustrates the preparation of a grease from the synthetic hydrocarbon lubricant of Example 1 using modified bentonite as the grease-forming agent. The modified bentonite used was Nykon 77 available from the Baroid Division of National Lead Company. Nykon 77 contains a small amount of sodium nitrite for rust inhibition.

The procedure used for preparing the grease of this example was as follows:

(1) Nykon 77 was blended thoroughly in about one-third of the synthetic hydrocarbon lubricant;

(2) One part acetone to seven parts of Nykon 77 of step (1) is then added and the total mass is mixed thoroughly;

(3) The admixture is then heated to 250 F., to remove the acetone;

(4) The resulting semifluid grease is cooled to about 180190 F., by adding additional synthetic hydrocarbon lubricant.

(5) Water, at 0.1 weight percent on total batch, is added and the batch milled and finished to consistency requirements.

Using the above-described procedure a grease was prepared containing 9.3 weight percent Nykon 77 and having a 60 stroke penetration of 313. This grease gave rust-free bearings when tested in the ASTMD-1743 rust test.

EXAMPLE 6 This example shows that the clay thickened-synthetic hydrocarbon lubricant greases have better low temperature flow properties than the corresponding lithium soap thickened greases.

The flow test apparatus used in this example consisted basically of a 20-foot coil of 0.19 inch I.D. copper tubing immersed in a refrigerated bath. A 24-foot pre-cooler coil of inch copper tubing was attached to the 20- foot coil, the pre-cooler coil also being immersed in the refrigerator bath. A variable speed gear pump (1 gallon per hour) was attached between the grease reservoir and the pro-cooler coil. A pressure gauge was attached at the junction of the pre-cooler coil and the 20-foot test coil. The gear pump was force-fed by putting air pressure on the grease reservoir to prevent cavitation. This pres sure did not influence the grease flow rate in the positive displacement gear pump. The grease flow rate in cubic inches per minute versus pressure drop per foot of test pipe was obtained. This flow rate can be converted to apparent viscosity.

Using the described apparatus the apparent viscosity of a clay-thickened grease and a lithium soap-thickened grease, of two consistencies, was obtained. All the greases used the synthetic hydrocarbon lubricant described in Example 1. The data are shown below.

APPARENI VISCOSITY Apparent viscosity, poises Nykon 77 Lithium Lithium Tempera- No. 1 No. No. 1 Shear rate, Secs ture, F. grease grease grease l Grease would not flow at -60 F.

The data in the above table shows that the apparent viscosity of the No. 1 clay-thickened grease is almost the same as the No. 0 lithium soap-thickened grease and significantly lower than the same consistency (Lo. No. 1) lithium soap-thickened grease.

EXAMPLE 7 Using the apparatus described in Example 6 it was determined that the No. 1 grade clay-thickened grease pumped at 63 F. even after overnight standing the pipe flow apparatus. The flow rate was 0.04 in. /min. at a pressure drop of 42 p.s.i./ft. Such a flow rate indicates that the grease is pumpable with a hand gun at --63 F.

EXAMPLE 8 This example shows the complete properties of several batches of greases of our invention which were prepared with the synthetic hydrocarbon lubricant of Example 1.

The invention having thus been described, what is claimed and desired to be secured by Letters Patent is:

1. A lubricating grease, said grease being pumpable at temperatures as low as 50 F., comprising a major proportion of a synthetic hydrocarbon lubricant and a greaseforming amount, in the range of from about 1 to about 25 weight percent, of a grease-forming agent selected from the group consisting of a lithium fatty acid soap and a modified clay, said synthetic hydrocarbon lubricant being prepared by the disproportionation of mono-n-alkylbenzenes, containing from 6 to 18 carbon atoms, using as the catalyst aluminum chloride, aluminum bromide or HF--BF said synthetic hydrocarbon lubricant having the following composition:

said synthetic hydrocarbon lubricant being characterized as having the following physical properties:

Viscosity index to 116. Pour point, F. 40 to -80. Molecular weight 350 to 460.

2. The lubricating grease of claim 1 characterized further in that the grease-forming agent is a lithium fatty acid soap.

3. The lubricating grease of claim 1 characterized further in that the grease-forming agent is a modified clay.

4. A lubricating grease, having excellent low temperature pumpability properties comprising a major proportion of a synthetic hydrocarbon lubricant and a greaseforming amount, in the range of from about 1 to about 25 weight percent, of a modified clay grease-forming agent, said synthetic hydrocarbon lubricant being prepared by the disproportionation of mono-n-alkylbenzenes, containing from about 10 to about 15 carbon atoms using as the catalyst aluminum chloride, aluminum bromide or HF-BF said synthetic hydrocarbon lubricant having the following composition:

said synthetic hydrocarbon lubricant being characterized as having the following physical properties:

The type of thickener, amount of thickener and properties Viscosity index 80 to 116. of the resulting greases are summarized in Table I, which Pour point, F. 40 to 80. follows: Molecular Weight 350 to 460.

TABLE I.-GREASE PROPERTIES Grease Test method A B C D E F Thlckener type Calcium Lithium Lithium Lithium Beutonite Bentonite Wt, percent 10 10 6 4. 5 10 9 NLGI grade No 2 2 1 0 2 1 t ir 270 320 360 285 315 10,000 strokes 285 335 375 300 325 RollPstabtilltty:

ene ra ion Change iASTM D4831 9 19 25 10 1 Dropping point, ASTM D-566 377 368 353 400+ 400+ Oil separation, perce ASTM D-1742 8. 7 16. 6 33. 5 7. 8 9. 9 Wheel brg. leakage, percent.-- ASTM D-1263 0. 43 4. 5 7. 55 2. 24 2. 75 Water washout at 77 F., percent ASIM D-1264 2. 5 3. 5 3. 25 1. 5 1. 75 Oxidation, p.s.l. drop at hours. ASTM D-942 3 4 4. 5 2 3 Copper corrosion FS-791a-5309 1A 1A 1A 1B 1B Four-ball, EP:

Wear, mm 0.5 0.51 0.55 0.52 0.61 0. 64

Weld, k 180 180 160 160 LWI 26. 4 22. 8 21. 3 24. 1 27. 8 28. 9

5. The lubricating grease of claim 4 wherein the modified clay grease-forming agent is modified bentonite.

6. The lubricating grease of claim 5 wherein the modified bentonite contains a rust-inhibiting amount of sodium nitrite.

7. The lubricating grease of claim 5 wherein the catalyst used to prepare the synthetic hydrocarbon lubricant is aluminum chloride.

8. A lubricating grease composition, having good low temperature pumpability properties, comprising a major proportion of a synthetic hydrocarbon lubricant, a greaseforming amount, in the range of from about 1 to about 25 weight percent, of a lithium fatty acid soap greaseforming agent and a rust-inhibiting amount of a combination of lead naphthenate, a fatty imidazoline alkyl diamine dicaprylate prepared from a fatty imidazoline alkyl diamine having the structure enyl, and a dialkyl dimethyl quaternary ammonium compound represented by the formula wherein R and R are C to C alkyl groups and X is nitrite or nitrate, said synthetic hydrocarbon lubricant being prepared by the disproportionation of mono-n-alkylbenzenes, containing from about 10 to about carbon atoms, using as the catalyst aluminum chloride, aluminum bromide or HF-BF said synthetic hydrocarbon lubri- 3 cant having the following composition:

Percent by wt. Di-n-alkylbenzenes 64 to 85. Alkyl-substituted tetrahydronaphthalenes and indanes 8 to 25. Indenes Less than 4.

Diphenylalkanes Less than 5.

said synthetic hydrocarbon lubricant being characterized as having the following physical properties:

Viscosity index 80 to 116. Pour point, F. 40 to 80. Molecular weight 350 to 460.

9. The lubricating grease composition of claim 8 wherein the lead naphthenate is present in the range of from about 1 to about 3 percent by weight, the dialkyl dimethyl quaternary ammonium compound is didodecyl dimethyl quaternary ammonium nitrite and is present in the range of from about 1 to about 4 percent by weight and the fatty imidazoline alkyl diamine dicaprylate is present in the range of from about 0.5 to about 2 percent by weight.

10. The lubricating grease composition of claim 9 wherein the catalyst used to prepare the synthetic hydrocarbon lubricant is aluminum chloride.

References Cited UNITED STATES PATENTS 2,141,593 12/1938 Clarke et a1. 252-59 2,810,769 10/1957 Sanford et a1. 252-59 2,810,770 10/1957 Sanford et al. 252-59 2,816,867 12/1957 Moore et a1. 208-19 2,967,827 1/1961 Bolt et al 252-28 3,173,965 3/1965 Pappas et al. 252-59 3,288,716 11/1966 Becraft et a1. 252-59 3,290,244 12/ 1966 Polishuk et al. 252- 3,316,294 4/1967 Feighner et a1 260-671 3,422,012 1/ 1969 Hopper et a1. 252-28 DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner U.X. Cl. X.R. 

